Facsimile machines, commonly called “fax” machines, communicate via an analogue communication network commonly called a “public switched telephone network” (PSTN).
A facsimile machine can be used to transmit an analogue signal representing a document printed on paper, via an analogue communication network, to another remote facsimile machine which is able to transcribe onto paper a copy of the document transmitted or faxed by the first facsimile machine.
However, with the development of IP telephony, or in other words of digital communication networks, a problem of compatibility arises. In fact, existing facsimile machines, designed to use an analogue communication network, cannot function on digital communication networks.